FREE SPREADSHEET COMPARE & VLOOKUP · 100% PRIVATE LOCAL PROCESSING
Compare Spreadsheets & Excel Files.
Two files, one clear answer.
Reconcile Excel and CSV files, look up values, and find missing records or duplicates. No complex formulas, no sign-up, and zero server uploads — your files stay on this device.
Excel + CSVDuckDB poweredFive-tab audit exportBring-your-own-AI SQL
01
Choose your sources
Source B
Or paste a column / table
Load one source for SQL or two for comparison. You can select the same workbook twice and choose different worksheets. CSV/TSV and .xlsx only. Beta limits: 75 MB per file, 500,000 rows and 250 columns per source.
02
Choose your workflow
Match columns between two files without formulas, or use your AI to write and run DuckDB SQL.
Load a spreadsheet in Step 01—or click —to unlock no-code column matching and the AI SQL context builder.
Load two files to match and compare. Load both Source A and Source B in Step 01 to pair columns, look up values, or export a five-tab reconciliation workbook.
Working with a single dataset? Switch to Query with SQL to query Source A or Source B immediately.
Tell us what to match
Choose matching columns and compare your files using the options below. No SQL required.
Pair columns, then select one or more matching keys. Keys stay as text. “Compare / add” selects fields to compare or bring over from B. Inferred types are suggestions; text is the default to preserve original values.
| Source A / profile | Source B | Matching key | Compare / add | Approved type |
|---|
Lookup keeps all rows in A and adds selected B columns under separate names. Approved cleaning and type conversions apply to mapped lookup output columns. Existing columns are never overwritten. Blank A keys remain as unmatched rows.
Comparison exports keep original A/B values. Cleaning and conversions affect matching and comparison. Blank keys never match. Repeated keys and their counterparts go to Duplicates.
Copy the dataset context into your AI chat and describe what you need. Paste the SQL it writes below, then run it here. You can also write your own query.
1. Copy your dataset context
Nothing is sent automatically. Copied context and sample rows are only shared where you paste them.
2. Run the query locally
Click a table badge to insert at cursor. Read-only DuckDB SQL against raw VARCHAR values; sources stay intact.
SELECT / WITH · Read-only
03
Your results
Changed fields are highlighted in the workbook. CSV exports protect against formula execution; Excel exports contain values, not formulas. Original workbook formatting, macros, and live formulas are not preserved.
From spreadsheet guesswork to a clear audit trail.
Look up without formulas
Match on a customer ID, email, or multiple columns. Add data from another export without writing VLOOKUP.
See every difference
Separate unchanged, missing, changed, and ambiguous records. Compare by identity rather than row position.
Keep the evidence
Download Matched, Only in A, Only in B, Changed, and Duplicates in one Excel workbook.
How to compare spreadsheets and perform VLOOKUPs online
Reconcile datasets, identify mismatched records, and enrich columns without formula syntax. All processing runs privately inside your browser memory.
Upload your spreadsheets
Drop or browse two files into Source A and Source B. We support Excel (.xlsx) and delimited text (.csv, .tsv, .txt) up to 75 MB and 500,000 rows per file. You can also paste copied table rows directly or select different worksheets from the same workbook. Your files never leave your computer.
Choose your comparison or lookup workflow
In Step 02, select Match & compare files to pair columns visually. Pick one or more matching key columns (such as Customer ID, SKU, or Email) and select which fields to compare or pull over from Source B. You can enable automatic whitespace trimming and case insensitivity, or set duplicate resolution policies when several matches occur.
Review and export the results
Click Run locally to inspect categorized counts and interactive tables grouped into Matched, Only in A, Only in B, Changed, and Duplicates. Download a multi-tab Excel workbook with modified fields highlighted, or save focused CSV extracts for reporting.
Common spreadsheet reconciliation use cases
Automated identity-based matching replaces manual row-by-row comparisons across finance, operations, sales, and data engineering workflows.
Month-end close & bank reconciliation
Match bank transactions against general ledger exports or payment provider settlements. Quickly flag unmatched disbursements, fee variances, and missing deposits with an organized audit trail.
Customer list deduplication & enrichment
Merge customer lists from Salesforce, HubSpot, or webinar exports. Look up missing attributes by email or account ID, isolate duplicate signups, and keep CRM contact records pristine.
Catalog & inventory audits
Compare supplier price sheets against active Shopify, Amazon, or ERP catalogs. Highlight discontinued SKUs, supplier price adjustments, and barcode changes before pushing live store updates.
Data migration & QA verification
Compare database exports before and after cloud migrations or ETL pipeline runs. Validate table row parity and detect truncated or shifted columns across legacy and target systems.
Why browser comparison beats complex Excel formulas
Formulas like VLOOKUP, XLOOKUP, and INDEX/MATCH work well for simple lookups, but large-scale reconciliations introduce common failure points that browser-based comparison solves:
Automatic whitespace & case normalization
Trailing spaces, leading tabs, and text-versus-number mismatches frequently trigger false #N/A errors in Excel. The tool trims and standardizes values so valid matches connect.
Explicit duplicate key detection
Standard lookup formulas stop at the first matching row, hiding duplicate records that distort totals. Ambiguous keys are isolated into a dedicated Duplicates tab so you can resolve them intentionally.
100% private local processing
Uploading financial records or customer lists to cloud utilities exposes sensitive PII and company data. All parsing and reconciliation here executes locally in your browser with zero server uploads.
Instant five-tab reconciliation workbook
Skip setting up complex conditional formatting rules across separate sheets. Export a five-sheet workbook separating matched rows, items only in A, items only in B, changed fields, and duplicates.
Frequently asked questions
Are my spreadsheets or CSV files uploaded to any server or cloud database?
No. All file reading, data normalization, row comparisons, and Excel workbook exports run entirely inside your browser's local memory using Web Workers and DuckDB WebAssembly. Your files never touch an external server.
How is this tool different from Excel's VLOOKUP, XLOOKUP, or INDEX/MATCH?
Excel formulas break easily on trailing whitespace, case differences, and mismatched data types, and can cause Excel to freeze on large files. This tool pairs columns visually without formulas, automatically normalizes data types, isolates duplicate keys, and exports a 5-tab audit trail.
What file formats and file sizes are supported?
You can compare Excel workbooks (.xlsx), comma-separated values (.csv), tab-separated values (.tsv), and plain text tables (.txt) up to 75 MB per file, with support for up to 500,000 rows and 250 columns per source.
What is included in the five-tab reconciliation workbook?
The exported Excel workbook contains five distinct sheets: 1) Matched (identical records), 2) Only in A (records present in Source A but absent from B), 3) Only in B (records present in Source B but absent from A), 4) Changed (records matching on key but differing in values, with changed cells highlighted), and 5) Duplicates (records with repeated keys requiring resolution).
How does the in-browser SQL querying with DuckDB work?
The tool embeds DuckDB compiled to WebAssembly inside your browser. You can execute read-only standard SQL queries directly against tables "A" and "B", or copy pre-formatted schema context into ChatGPT or Claude to generate queries for you.
Can I compare two different worksheets within the same Excel workbook?
Yes. Simply load the same Excel (.xlsx) file into both Source A and Source B, then select a different worksheet from the dropdown menu on each source card.
How are duplicate keys and blank cells handled during comparison?
Blank keys never match and are flagged for review. For duplicate keys in Source B during lookups, you can choose to halt and resolve, use the first matching row, use the last matching row, or return all matches. In comparison mode, all repeated keys and their counterparts are isolated into the Duplicates sheet.
Documenting spreadsheet workflows or sharing audit walkthroughs?
Record your screen, voice, and camera with BMT Screen Recorder. Share instant browser playback links with automatic pause removal and zero upload wait times.